Lapatinib or trastuzumab? Which anti-HER2 treatment is more effective in the treatment of patients with HER2-positive breast cancer with brain metastases? An Anatolian Society of Medical Oncology Study.

638 Background: In the present study, we investigate that which treatment choice is more effective in the human epidermal growth factor receptor 2 (HER2) positive breast cancer patients with brain metastases. Methods: Of 405 metastatic breast cancer patients with brain metastases at referral centers in Turkey, 111 patients treated with lapatinib or trastuzumab after brain metastases eligible for the analyses were identified. Patients received both drugs consecutively or sequentially were excluded from the study. Results: Median age was 44 years (27-76) and 46 of the 111 patients (41.5%) had received lapatinib. Median time to development of brain metastases was 12.2 months (0-71). Sixteen patients (14.4%) had undergone surgery, 33 (29.7%) radiosurgery, and 108 (97.2%) whole brain radiation therapy (WBRT). Median overall survival (OS) after brain metastases was 15 months(95% confidence interval (CI): 12.3-17.6). Lapatinib usage was prolonged OS over trastuzumab alone (19.1 months vs 12 months, p=0.039).Other parameters affecting the survival were Karnofsky performance score (KPS, >70), number of brain metastases (>3), extracranial metastases (≥2), performed neurosurgery, and received radiosurgery. After correction for potential confounders, lapatinib therapy remained an independent positive predictor for survival [Odds ratio (OR), 0.57; p=0.02). Conclusions: Although this retrospective multi-center study had several limitations, study results suggest that the usage of lapatinib after brain metastases prolonged survival compared to the usage of trastuzumab. This result should be support with prospective studies.